Diffusion Barrier

ABSTRACT

The migration of residue from the vaporization of e-liquid is impeded from migration into an e-liquid reservoir through the introduction of a diffusion barrier. This barrier slows or stops the migration of the residue so that the expected life of the pod will have expired before the residue can migrate into the reservoir and cause fouling of the e-liquid which is often manifested as a discoloration of the e-liquid.

CROSS REFERENCE TO RELATED APPLICATIONS

This is the first application for the instant invention.

TECHNICAL FIELD

This application relates generally to a pod for storing atomizable liquid for use in a vaporizer system, and more particularly to a vaping system pod having a diffusion barrier to prevent migration of flavors for use in conjunction with an electronic cigarette or vaporizer.

BACKGROUND

Electronic cigarettes and vaporizers are well regarded tools in smoking cessation. In some instances, these devices are also referred to as an electronic nicotine delivery system (ENDS). A nicotine based liquid solution, commonly referred to as e-liquid, often paired with a flavoring, is atomized in the ENDS for inhalation by a user. In some embodiments, e-liquid is stored in a cartridge or pod, which is a removable assembly having a reservoir from which the e-liquid is drawn towards a heating element by capillary action through a wick. In many such ENDS, the pod is removable, disposable, and is sold pre-filled.

In some ENDS, a refillable tank is provided, and a user can purchase a vaporizable solution with which to fill the tank. This refillable tank is often not removable, and is not intended for replacement. A fillable tank allows the user to control the fill level as desired. Disposable pods are typically designed to carry a fixed amount of vaporizable liquid, and are intended for disposal after consumption of the e-liquid. The ENDS cartridges, unlike the aforementioned tanks, are not typically designed to be refilled. Each cartridge stores a predefined quantity of e-liquid, often in the range of 0.5 to 3 ml. In ENDS systems, the e-liquid is typically composed of a combination of any of vegetable glycerine, propylene glycol, nicotine and flavorings. In systems designed for the delivery of other compounds, different compositions may be used. In some systems, a carrier solution (which may be composed of at least one of vegetable glycerine and propylene glycol) is used to carry cannabinoids and optionally terpenes.

In the manufacturing of the disposable cartridge, different techniques are used for different cartridge designs. Typically, the cartridge has a wick that allows e-liquid to be drawn from the e-liquid reservoir to an atomization chamber. In the atomization chamber, a heating element in communication with the wick is heated to encourage aerosolization of the e-liquid. The aerosolized e-liquid can be drawn through a defined air flow passage towards a user’s mouth.

FIGS. 1A, 1B and 1C provide front, side and bottom views of an exemplary pod 50. Pod 50 is composed of a reservoir 52 having an air flow passage 54, and an end cap assembly 56 that is used to seal an open end of the reservoir 52. End cap assembly has wick feed lines 58 which allow e-liquid stored in reservoir 52 to be provided to a wick (not shown in FIG. 1 ). To ensure that e-liquid stored in reservoir 52 stays in the reservoir and does not seep or leak out, and to ensure that end cap assembly 56 remains in place after assembly, seals 60 can be used to ensure a more secure seating of the end cap assembly 56 in the reservoir 52. In the illustrated embodiment, seals 60 may be implemented through the use of o-rings.

As noted above, pod 50 includes a wick that is heated to atomize the e-liquid. To provide power to the wick heater, electrical contacts 62 are placed at the bottom of the pod 50. In the illustrated embodiment, the electrical contacts 62 are illustrated as circular. The particular shape of the electrical contacts 62 should be understood to not necessarily germane to the function of the pod 50.

Because an ENDS device is intended to allow a user to draw or inhale as part of the nicotine delivery path, an air inlet 64 is provided on the bottom of pod 50. Air inlet 64 allows air to flow into a pre-wick air path through end cap assembly 56. The air flow path extends through an atomization chamber and then through post wick air flow passage 54.

A mouthpiece 68 is illustrated in section sitting atop pod 50, with an absorbent pad 66 between the two. Absorbent pad 66 facilitates the absorption of large droplets and of any condensation of e-liquid that occurs during and after the use of the pod 50. The mouthpiece has apertures to allow the airflow through the pod to be delivered to the user. By selecting a location for the apertures, a curve can be introduced into the airflow, which may discourage the delivery of large droplets that are often associated with spitback.

FIG. 2 illustrates a cross section taken along line A in FIG. 1B. This cross section of the device is shown with a complete (non-sectioned) wick 66 and heater 68. End cap assembly 56 resiliently mounts to an end of air flow passage 54 in a manner that allows air inlet 64 to form a complete air path through pod 50. This connection allows airflow from air inlet 64 to connect to the post air flow path through passage 54 through atomization chamber 70. Within atomization chamber 70 is both wick 66 and heater 68. When power is applied to contacts 62, the temperature of the heater increases and allows for the volatilization of e-liquid that is drawn across wick 66.

Typically the heater 68 reaches temperatures well in excess of the vaporization temperature of the e-liquid. This allows for the rapid creation of a vapor bubble next to the heater 68. As power continues to be applied the vapor bubble increases in size, and reduces the thickness of the bubble wall. At the point at which the vapor pressure exceeds the surface tension the bubble will burst and release a mix of the vapor and the e-liquid that formed the wall of the bubble. The e-liquid is released in the form of aerosolized particles and droplets of varying sizes. These particles are drawn into the air flow and into post wick air flow passage 54 and towards the user.

FIG. 3 illustrates an alternate embodiment of pod 50, shown in cross section. Pod 50 is comprised of a reservoir 52 having a post-wick air passage 54. An end cap 56 is inserted into the bottom end of the reservoir 52 to seal the pod 50, typically after filling the reservoir 52 with e-liquid. The end cap 56 has wick feed lines 58 to allow e-liquid from the reservoir 52 to enter the end cap 56 to make contact with wick 72. Electrical leads 62 allow power to be provided to pod 50 and generate heat in heater 74. As with the earlier described embodiments, this generates bubbles within the e-liquid atop the heater 74.When a bubble reaches a size determined by a number of physical characteristics, it will rupture. These characteristics include a number of properties of the e-liquid, but effectively a bubble will rupture when the surface tension of the e-liquid (forming the bubble) is no longer sufficient to overcome the increasing vapor pressure inside the bubble. This rupturing of the bubble will result in the release of a quantity of e-liquid, as well as e-liquid droplets of varying sizes from what was the surface of the bubble. Because in most vaping devices, the application of power to heater 74 is tied to the user drawing on the vaping device, the vapor and droplets are entrained within an airflow through pre-wick airflow passage 64, into atomization chamber 70 and out through post wick airflow passage 54.

This illustrated embodiment differs from the previously illustrated embodiment in that in place of using O-rings as seals, a resilient cap 76 is employed. This resilient cap may be made of a material such as silicone that can deform under pressure, but will typically return to its original shape. Resilient cap 76 is sized to fit atop end cap 56, so that when inserted into reservoir 52, the resilient cap 76 will be deformed, and will provide a seal to mitigate leakage of e-liquid. The resilient cap 76 is also used in this illustrated embodiment to provide an airflow feature 78 into a post-wick airflow path. In other embodiments, the airflow feature could be integrated into the post-wick airflow path 54 for a similar, or the same, effect. A blunt airflow feature allows the e-liquid laden airflow to be interrupted and for vortices to be introduced into the airflow within the post wick airflow passage 54. These vortices can encourage larger droplets within the airflow to be pushed into or towards the sidewalls of post wick airflow passage 54, which can act to remove droplets associated with spitback or other undesirable phenomena from the e-liquid laden airflow.

As noted above, the e-liquid is delivered to the user in two forms: a vapor caused by the heating of e-liquid, and droplets of varying sizes caused by the vapor rupturing the surface of the bubble. The e-liquid is a solution of a number of different components, each of which can have its own specific vaporization temperature. Typically the temperature of the heater is set to allow for vaporization of a component such as the propylene glycol as it represents the largest fraction of the e-liquid. This allows for the vaporization to occur quickly, and results in good droplet production. Some of the components may be either dissolved in the e-liquid solution or carried in suspension within the e-liquid solution. These components may not evaporate at the heater when the e-liquid itself is volatilized. As a result, the portion of the e-liquid that is turned to a vapour is likely to leave behind a precipitate. This precipitate is often a flavorant or a compound used to provide a sweetness to the vaping experience. The resultant precipitate will accumulate at the site of the evaporation.

As the number of heating cycles increases, the amount of precipitate that is left behind increases. It has been observed that some vaping systems will accumulate a residue that becomes darker over time. It is believed that this residue may be a result of the burning of this precipitate. The heating of the precipitate may result in more than an aesthetically unpleasant buildup residue. The residue itself is subjected to the heating cycle intended to vaporize e-liquid, which often involves temperatures in excess of 200° C. This may result in either a “caramelization” of the sugars and sugar substitutes. It should be understood that this residue may burn without burning the substrate of the wick 72. This creates two different pathways for combustion that would result in a so-called burnt hit, the first being combustion involving material within the wick 72, such as cotton, and the second being the burning of the residue. It may also be possible for both of these to burn together, but it is not believed to be a requirement for them to burn together.

It should be understood that the wick 72 is in fluid communication with the e-liquid stored within the reservoir 52. As a result, when the e-liquid within the wick 72 is replenished, the residue discussed above can migrate through the wick 72 and may then contaminate the e-liquid within reservoir 52. This contamination may result in discoloration of the e-liquid within the reservoir 52, and in some cases it may result in a change in the flavor of the e-liquid. This is an undesirable effect that is often based on the manner in which the e-liquid is consumed, the design of the pod, the rate of e-liquid consumption and many other factors. As a result of the number of factors associated with this contamination, it is a difficult process to prevent, and it may only intermittently affect some users.

This contamination effect can result in users becoming concerned or upset about the quality of the e-liquid or the vaping system itself. It would therefore be beneficial to have a mechanism to prevent the migration of residue from the wick into the e-liquid within the reservoir.

SUMMARY

It is an object of the aspects of the present invention to obviate or mitigate the problems of the above-discussed prior art.

Through the use of a barrier between the wick and the reservoir, migration of residue from the atomization of liquids from the wick into the reservoir is impeded. This barrier can perform any of a number of functions including slowing the movement of e-liquid carrying the residue, filtering residue from e-liquid migrating through the barrier, and preventing movement of e-liquid in one direction. In this way, the barrier can prevent the fouling of the e-liquid within the reservoir which may cause at least one of flavor changes to e-liquid within the reservoir and visual changes to the color of the stored e-liquid.

In a first aspect of the present invention, there is provided a pod for storing atomizable liquid. This pod is designed for use within a vaping system and comprises a reservoir, a heater, a wick, and a diffusion barrier. The reservoir is used to store the atomizable liquid. The wick is in fluid communication with the atomizable liquid stored within the reservoir and draws the atomizable liquid from the reservoir towards the heater, which can be used to atomize the atomizable liquid. The diffusion barrier, in some embodiments, is distinct from the wick, and is interposed between the wick and the reservoir. The barrier can resist or impede migration of residue resulting from atomization of the atomizable liquid from the wick into the atomizable liquid within the reservoir.

In an embodiment of the first aspect of the present invention, the atomizable liquid is an e-liquid comprising at least one of vegetable glycerine, propylene glycol, nicotine and a flavorant. In another embodiment, the atomizable liquid comprises a cannabinoid.

In another embodiment, the heater is aligned with an airflow path through the pod to allow atomized liquid to be entrained in an airflow in the airflow path. In some embodiments, the diffusion barrier is a sponge comprising spun nylon, and is optionally in physical contact with first and second ends of the wick and in some embodiments it may occlude a wick feed line between the reservoir and the wick. In some embodiments, the diffusion barrier does not contact the wick, and may optionally occlude a wick feed line between the reservoir and the wick.

In another embodiment, the diffusion barrier is situated in the reservoir, and optionally may be a membrane such as a semi permeable membrane. The membrane may comprise expanded polytetrafluoroethylene. It should be understood that reference to a semi permeable membrane should also be understood to mean that the membrane allows e-liquid to travel through the membrane in one direction but not in the other. In further embodiments, the membrane allows movement of the e-liquid in both directions, but that there is a directional preference so that the e-liquid can move more freely in one direction than the other.

In a further embodiment, the barrier is a spun nylon sponge. In another embodiment, the barrier is comprised of at least one of cotton, nylon, wool, linen, and hemp. In some embodiments, the wick is vertically aligned within the pod around an airflow path through the pod. Optionally the diffusion barrier forms a ring around the wick, and the diffusion barrier may isolate the wick from the reservoir.

In a second aspect of the present invention, there is provided a vaporizer system for atomizing an atomizable liquid. The vaporizer systems comprises a battery, a reservoir, a heater, control circuitry, a wick and a diffusion barrier. The battery is used for storing power. The reservoir is used for storing the atomizable liquid. The heater is used to atomize the atomizable liquid in response to receipt of power from the battery. The control circuitry can be used to control the application of from the battery to the heater in response to an indication of use. The wick draws atomizable liquid from the reservoir towards the heater. The diffusion barrier is distinct from the wick, and is interposed between the wick and the reservoir. The diffusion barrier impedes migration of residue resulting from atomization of the atomizable liquid from the wick into the atomizable liquid within the reservoir.

In some embodiments of the second aspect, the control circuitry is embodied within a processor that can execute stored instructions to carry out control of the application of power to the heater.

It should be understood that embodiments of the first aspect can be applied, with suitable modifications that would be apparent to those skilled in the art, to the second aspect.

BRIEF DESCRIPTION OF THE DRAWINGS

The patent or application file contains at least one drawing executed in color. Copies of this patent or patent application publication with color drawing(s) will be provided by the Office upon request and payment of the necessary fee.

Embodiments of the present invention will now be described in further detail by way of example only with reference to the accompanying figure in which:

FIG. 1A is a front view of a prior art pod for use in an electronic nicotine delivery system;

FIG. 1B is a side view of the pod of FIG. 1A;

FIG. 1C is a bottom view of the pod of FIG. 1A;

FIG. 2 is a cross section of the pod of FIGS. 1A and 1B along cut line A in FIG. 1B;

FIG. 3 is a cross section view of an alternate embodiment of the pod illustrated in FIGS. 1A-C and 2 ;

FIG. 4 illustrates a cross section view of a pod according to a non-limiting embodiment of the present invention;

FIG. 5A illustrates a front cross section view of a pod according to an alternate non-limiting embodiment of the present invention;

FIG. 5B illustrates a side view cross section of a wick and diffusion barrier as illustrated in FIG. 5A;

FIG. 6 illustrates a front cross section view of a pod according to an alternate non-limiting embodiment of the present invention; and

FIG. 7 illustrates a front cross section view of a pod according to an alternate non-limiting embodiment of the present invention; and

FIG. 8A illustrates a front view of a diffusion barrier wick according to an alternate non-limiting embodiment of the present invention;;

FIG. 8B illustrates a cross section of the wick of FIG. 8A taken along section line 8B; and

FIG. 8C illustrates a cross section of the wick of FIG. 8B taken along section line 8C.

DETAILED DESCRIPTION

In the instant description, and in the accompanying figures, reference to dimensions may be made. These dimensions are provided for the enablement of a single embodiment and should not be considered to be limiting or essential. Disclosure of numerical range should be understood to not be a reference to an absolute value unless otherwise indicated. Use of the terms about or substantively with regard to a number should be understood to be indicative of an acceptable variation of up to ±10% unless otherwise noted.

To address issues associated with the back migration of residue, left with the wick after atomizing e-liquid, through the wick and into the e-liquid within the reservoir, various embodiments described below will introduce a diffusion barrier that allows e-liquid to enter the wick, but resists the migration of the residue through the wick and into the e-liquid. It should be understood that a diffusion barrier may simply slow the back migration, as the contents of the reservoir are finite, and so long as the back migration is sufficiently slowed, the residue will not be provided an opportunity to foul the e-liquid before the e-liquid is consumed. Even if the pod in question is a refillable pod, there is a lifespan associated with the pod, so back propagation is only necessary for a finite time.

In some embodiments the diffusion barrier will be integrated within the wick to create a wick with directional capillary action, so that the capillary action of the wick draws e-liquid towards the center of the wick and resists the flow of e-liquid (and especially residue dissolved within the e-liquid) from the center of the wick outwards.

FIG. 4 is a cross-sectional view of a pod 100 that impedes back migration of residues from the wick into the reservoir. Pod 100 has a reservoir 102 which defines a post-wick airflow passage 104. Reservoir 102 can be filled with e-liquids and then sealed through the insertion of end cap 106. End cap 106 includes wick feed lines 108 that allow e-liquid from the reservoir 102 to be supplied to wick 116. Power can be provided to pod 100 through electrical leads 110, which are connected to heater 118 which engages with wick 116 so e-liquid saturating the wick 116 can be properly volatilized by the heating of heater 118. Airflow through the pod 100 starts with pre-wick airflow passage 114, proceeds to atomization chamber 114 where it passes over the heater 118 and wick 116. Airflow then continues into post wick airflow passage 104. End cap 106 forms a sealing engagement with the reservoir 102, which in the illustrated embodiment is aided by the presence of resilient cap 120, which can be made of a physically resilient material such as silicone. The resilient cap 120 can be fitted atop end cap 106 so that when inserted into reservoir 102, the resilient cap is at least partially compressed, resulting in a sealing engagement designed to prevent egress of the e-liquid from any gaps between the end cap 106 and reservoir 102. Within resilient cap 120, an airflow feature 122 is introduced, so that the airflow passing over wick 116 and heater 118 impacts upon the feature 122. This airflow feature, although shown as being implemented in resilient cap 120 may also be introduced into post wick airflow passage 104. When an airflow passes over wick 116 and heater 118, it entrains e-liquid in the form of droplets of varying sizes. Some of these droplets are of a size that is associated with poor user experiences. To avoid providing the user with droplets that are too large, airflow feature 122 creates turbulence in the post wick airflow, and may cause vortices to form. These vortices cause e-liquid droplets over a threshold size to be pushed into the walls of post wick airflow passage 104, thus removing them from the airflow.

Diffusion barrier 124 is shown as having been inserted into the wick feed lines 108. E-liquid from reservoir 102 can saturate diffusion barrier 124, and then fill wick feed lines 108, allowing wick 116 to draw e-liquid across itself through capillary action. Diffusion barrier 124 is, as discussed above, intended to slow or restrict the migration of at least some of the built-up residue, from wick 116 into the e-liquid within reservoir 102. Residues may be associated with precipitate formed from the heating of e-liquid to a vapor state. The vapor from a nicotine based e-liquid is largely the carrier liquid, with additions such as flavorants and even possibly nicotine failing to vaporize. The flavorants and nicotine are delivered in the droplets associated with the rupture of the bubbles. As more e-liquid is drawn through wick 116, the amount of precipitate left on or near the heaters increases. Due to the presence of flavorants and sweeteners, the precipitate may have a tendency to effectively cook in the presence of the heating and cooling cycles, forming a residue that can be seen on the wick 116 as a dark section. To the touch, this cooked residue is sticky, and may leave a mark on other surfaces used to touch the wick 116. It should be noted that the precipitate is at least partially soluble in e-liquid, as at least some of the components of the residue are left behind from the vaporization of e-liquid. As e-liquid is drawn across the wick 116, it is able to dissolve at least some of the residue components, helping to spread the residue across the wick 116. This reduces the apparent concentration of the residue, but increases an overall perception of discoloration within the wick.

As the residue reaches the outer edges of wick 116, the residue can be carried out of wick 116 and into e-liquid within wick feed lines 108. While wick 116 is often made of materials such as cotton, linen, hemp, wool, nylon and other bulk materials, diffusion barrier 124 may be differently formed. In some embodiments diffusion barrier may be an engineered material that forms a semipermeable barrier allowing a one way path for e-liquid from the reservoir 102 to the wick feed lines 108 and wick 116. It should be understood that in some embodiments it may not be possible or feasible to have a true one way path for e-liquid, and a directionally preferred path may be provided so that e-liquid can move through the barrier more freely in one direction (e.g. from the reservoir 102 to the feedlines 108) than the other. In other embodiments the diffusion barrier 124 may be formed of a nylon sponge that slows the movement of e-liquid between the reservoir 102 and the wick feed line 108 / wick 116. In such an embodiment, nylon sponges 124 are placed within wick feed lines 108 so that they also optionally extend into reservoir 102. E-liquid within reservoir 102 will saturate the nylon sponge 124 and migrate into wick feed lines 108, helping to saturate the wick 116. The characteristics of the nylon sponge diffusion barrier, including a saturation speed, can be defined through properties such as the density of the sponge. Residue that is drawn outwards through sponge 116 may be able to visually foul e-liquid within the feedlines 108, but will be less likely to be able to migrate through diffusion barrier 124. As the device is used, e-liquid from the feedlines 108 is drawn across the wick 116, and e-liquid within nylon sponge 124 will drip into feed lines 108 through gravity, to aid in replenishing the e-liquid available to the wick 116. Nylon sponges 124 will remain saturated with e-liquid as they are also in contact with the e-liquid within reservoir 102.

It should be noted that a variety of different materials could be used for diffusion barrier 124 including cotton, nylon, wool, linen, hemp and other materials that may take the form of a sponge, or may be woven into sheets and then rolled up and inserted into the wick feed lines 108. Other embodiments, which will be described in more detail below, may make use of materials that may be conventionally described as membranes.

Some pod designs make use of a so-called cartomizer matrix within reservoir 102 to hold an e-liquid. The wick is inserted into the cartomizer matrix to maximize the potential for the wick to absorb e-liquid. The cartomizer matrix is typically used so that a less viscous e-liquid can be used without increasing the likelihood of e-liquid leaking from the pod. This structure of using a cartomizer matrix to have a large interface area with the wick is used in the embodiment of FIG. 5A. Although pod 100 has a similar structure to that shown in FIG. 4 , a cartomizer matrix based diffusion barrier 126 is used in place of diffusion barrier 124. The cartomizer matrix based diffusion barrier 126 extends through wick feedline 108 and optionally extends into reservoir 102. This allows the diffusion barrier 126 to absorb e-liquid from reservoir 102 and hold it within wick feedlines 108. Much as with the previous embodiment, e-liquid consumed can be replaced by the wick 116 drawing e-liquid that is carried within or across the diffusion barrier 126. As shown in FIG. 5B, the wick 116 is surrounded by a heater 118 which in the illustrated embodiment takes the shape of a coil. The diffusion barrier 126 is formed to allow insertion of the wick 116 into the matrix. In such embodiments it may be possible for the interface area to be increased through fanning of the end of wick 116 as it engages with diffusion barrier 126.

While residue may be drawn across wick 116, diffusion of e-liquid (or residue borne by e-liquid) across barrier 126 is relatively slow, thus preventing residue-bearing e-liquids free movement across diffusion barrier 126 and into the e-liquid within reservoir 102. It should be noted that residue carried by e-liquid leaving the wick 116 may in some circumstances enter into diffusion barrier 126 where the residue may be left behind, with diffusion barrier 126 acting to some extent as a filter. By causing a slowed migration of the e-liquid into the reservoir 102, diffusion barrier 126 reduces the likelihood of fouling the e-liquid within the reservoir 102.

In FIG. 6 , a similar pod structure to that illustrated in FIGS. 4 and 5A is presented. A different diffusion barrier 128 is employed. Diffusion barrier 128 sits atop the end cap 106 and resilient cap 120. This provides a similar form of protection to that shown in FIG. 4 , but the diffusion barrier 128 can be formed differently, and in some situations, it may provide for a simpler manufacturing process. In some embodiments, diffusion barrier 128 may resemble a membrane that allows for different rates of diffusion in different directions.

Diffusion barrier 128 may be implemented as a barrier that allows the weight of e-liquid within reservoir 102 to push e-liquid through a one-way barrier 128. It should be understood that in this embodiment, barrier 128 may be acting as a barrier to net total transport in the direction moving towards reservoir 102. Thus diffusion barrier 128 may function like an expanded polytetrafluoroethylene (ePTFE) material such as Gore-Tex™ or another so-called durable liquid resistant barrier. In such an embodiment, barrier 128 is oriented so that the large pores are facing into the reservoir, and the smaller aperture pores face into the wick feed lines 108. This allows for the migration of e-liquid into the feed line 108 so that e-liquid from reservoir 102 can replenish wick 116, but e-liquid fouled with residue cannot as easily cross the barrier 128 and foul the e-liquid within reservoir 102. When inverted, there is a much smaller amount of e-liquid atop barrier 128, and the e-liquid is facing smaller sized pores to enter barrier 128. This greatly reduces the risk of residue migrating through the barrier 128 in sufficient quantities to foul the e-liquid within the reservoir.

FIG. 7 illustrates a cross section of pod 140 that makes use of a vertically oriented wick 152. Pod 140 has a reservoir 142 for storing e-liquid. Within pod 140 is a post wick airflow passage 144. Upon being filled with e-liquid, end cap 146 can be inserted. The sealing mechanisms used by end cap 146 and reservoir 142 are not shown in FIG. 7 as they are not germane to the current discussion of this figure. As with previous figures, electrical leads 148 connect to the heater 154 which is in engagement with wick 152. A pre-wick airflow passage 150 aligns with both the interior of wick 152 and the post wick airflow passage. In operation, power is delivered across the electrical leads 148 and heater 154 will volatilize e-liquid drawn across wick 152. Residue that may form is likely to form on the interior of the wick 152, and it will migrate outwards across a narrow width of wick 152. Where in prior art embodiments, the residue would then be in contact with the e-liquid stored within reservoir 142, in the illustrated embodiments, a diffusion barrier 156 prevents or retards the movement of residue from the wick 152 into the reservoir 142. In some embodiments, diffusion barrier 156 is a material similar to a cartomizer matrix, that is a sponge of nylon or concentrically wound layers of a wicking fabric such as cotton, linen, wool or other such material.

As before the speed with which e-liquid can migrate through the diffusion barrier 156 is either directionally based, or it is slowed by the diffusion barrier matrix. By at least slowing the movement of e-liquid from the wick back into the reservoir 142, residue is prevented from entering the reservoir, preventing (or at least delaying) the visual fouling of the e-liquid.

FIGS. 8A-C present an alternate embodiment of the present invention, in which the characteristics of the diffusion barrier 124, 126 and 128 can be integrated within a wick 130. A pod including such a wick could be used in a conventional pod that may or may not make use of a distinct diffusion barrier between the wick and the e-liquid within the reservoir. Wick 130 uses capillary action to draw e-liquid from the outer edges towards the middle of wick 130 where the e-liquid can be heated by heater 132. Residue that may form from the heating process will form in the middle of wick 130. However, unlike previously described wicks, wick 130 is designed with capillaries 134 that are shaped to encourage e-liquid to be drawn in from the outside edges of wick 130 towards the middle of wick 130. This helps prevent the outwards migration of any residue formed during the heating process.

FIG. 8B illustrates a cross section of the wick 130, surrounded by heater 132 at section line 8B. The wick 130 is formed to have capillary passages 134 that at this location within wick 130 are relatively large, and that effectively dominate the profile of the wick 130. FIG. 8C illustrates a cross section of the wick 130, surrounded by heater 132 at section line 8C. The wick 130 has capillary passages 134 that are smaller than they were in FIG. 8B, resulting in a greater amount of wick 130 in the profile at this point. This reduction in the sizes of capillaries 134 can be achieved through a number of different techniques. In some embodiments, a wick 130 made of materials such as cotton, hemp, linen, wool, and synthetic fibers such as nylon, can be compressed (possibly using the winding of heater 132 to create the compression) so that the capillaries become compressed and smaller in the middle of the wick, and larger and less compressed near the edges.

In other embodiments wick 130 may be made of a material such as a ceramic in which the sizes of capillaries can be controlled in the manufacturing process. In some embodiments, the wick 130 may be formed of a resin or polymer coating on the heater 132, with grooves on the surface (and possibly within) the resin or polymer to act as capillaries. In such wicks, the sizing and spacing of the capillaries can be engineered to allow for the capillary profiles discussed above.

In other embodiments, wick 130 may be made of materials such as glass fibers that can be manufactured with different profiles along their length. This would allow for the selection of fibers that are narrower in profile at at least one end than they are in the middle. This would create capillaries between the fibers that narrow from at least one of the ends towards the middle of the wick 130. It should be noted that a similar structure may also be possible using a wick 130 made up of carbon fiber or other such materials.

As noted above, there are many different embodiments for a wick 130 depending on the choice of the material of manufacture.

It should be appreciated that in the above embodiments, the problem of residue migrating from near the heater, through the wick and back into the e-liquid within the reservoir are mitigated through the use of a diffusion barrier. This barrier is interposed between the wick and the reservoir, allowing for the barrier to resist the migration of residue into the e-liquid within the reservoir. The barrier slows or prevents migration of the residue in any of a number of different ways including preferentially permitting flow of e-liquid from the reservoir towards the wick, slowing the flow of e-liquid, filtering the residue from e-liquid during migration through the barrier. This allows for the migration of residue to be sufficiently slowed that during the course of the finite life of the pod, the residue is impeded from fouling e-liquid within the reservoir. In some embodiments this is done with a horizontal wick, while in others it is implemented with a vertical wick. This can be used for both nicotine bearing e-liquid as well as an atomizable liquid carrying cannabinoids.

It should also be understood that this arrangement using a diffusion barrier could be implemented in any of a non-refillable pod, a refillable pod, and a vaporizing system that has a reservoir integrated into the overall device having a battery and a control circuitry that may take the form or a processor, or even simply using a pressure sensor or switch to modulate power from the battery to the heater.

Although presented below in the context of use in an electronic nicotine delivery system such as an electronic cigarette (e-cig) or a vaporizer (vape) it should be understood that the scope of protection need not be limited to this space, and instead is delimited by the scope of the claims. Embodiments of the present invention are anticipated to be applicable in areas other than ENDS, including (but not limited to) other vaporizing applications.

In the instant description, and in the accompanying figures, reference to dimensions may be made. These dimensions are provided for the enablement of a single embodiment and should not be considered to be limiting or essential. The sizes and dimensions provided in the drawings are provided for exemplary purposes and should not be considered limiting of the scope of the invention, which is defined solely in the claims. 

1. A pod, for storing an atomizable liquid, for use within a vaping system, the pod comprising: a reservoir for storing the atomizable liquid; a heater for atomizing the atomizable liquid; a wick for drawing atomizable liquid from the reservoir towards the heater; and a diffusion barrier, distinct from the wick, interposed between the wick and the reservoir for impeding migration of residue resulting from atomization of the atomizable liquid from the wick into the atomizable liquid within the reservoir.
 2. The pod of claim 1 wherein the atomizable liquid is an e-liquid comprising at least one of vegetable glycerine, propylene glycol, nicotine and a flavorant.
 3. The pod of claim 1 wherein the atomizable liquid comprises a cannabinoid.
 4. The pod of claim 1 wherein the heater is aligned with an airflow path through the pod to allow atomized liquid to be entrained in an airflow in the airflow path.
 5. The pod of claim 1 wherein the diffusion barrier is a sponge comprising spun nylon.
 6. The pod of claim 5 wherein the diffusion barrier is in physical contact with first and second ends of the wick.
 7. The pod of claim 6 wherein the diffusion barrier occludes a wick feed line between the reservoir and the wick.
 8. The pod of claim 5 wherein the diffusion barrier does not contact the wick.
 9. The pod of claim 8 wherein the diffusion barrier occludes a wick feed line between the reservoir and the wick.
 10. The pod of claim 1 wherein the diffusion barrier is situated in the reservoir.
 11. The pod of claim 10 wherein the diffusion barrier is a membrane.
 12. The pod of claim 11 wherein the membrane preferentially allows movement of the e-liquid in one direction.
 13. The pod of claim 11 wherein the membrane comprises expanded polytetrafluoroethylene.
 14. The pod of claim 1 wherein the barrier is a spun nylon sponge.
 15. The pod of claim 1 wherein the barrier is comprised of at least one of cotton, nylon, wool, linen, and hemp.
 16. The pod of claim 1 wherein the wick is vertically aligned within the pod around an airflow path through the pod.
 17. The pod of claim 1 wherein the diffusion barrier forms a ring around the wick.
 18. The pod of claim 17 wherein the diffusion barrier isolates the wick from the reservoir.
 19. A vaporizer system for atomizing an atomizable liquid, the vaporizer comprising: a battery for storing power; a reservoir for storing the atomizable liquid; a heater for atomizing the atomizable liquid in response to receipt of power from the battery; control circuitry for controlling application of power from the battery to the heater in response to an indication indicative of use; a wick for drawing atomizable liquid from the reservoir towards the heater; and a diffusion barrier, distinct from the wick, interposed between the wick and the reservoir for resisting migration of residue resulting from atomization of the atomizable liquid from the wick into the atomizable liquid within the reservoir. 